Prospects for methadone maintenance patients completing detoxification and initiating a drug-free adjustment are less than 50% in outcome studies and completion rates range to 19%. Research proposed here has direct implications and practical application for improving detoxification outcome. Since maintenance was first used, investigators discovered increased anxiety at prospects of detoxification. Cushman and Dole (1973) found 11% of their sample of rehabilitated maintenance patients aborted detoxification because of increased anxiety. Investigators subsequently identified detoxification fear's correlates and developed reliable and valid measures for it, suspecting it as one of the culprits in poor maintenance detoxification outcome. But to date we have no direct evidence of detoxification fear's role in detoxification outcome. We will follow a random sample cohort of 271 treated addicts in 3 large maintenance programs from our previous research and discover their methadone maintenance and detoxification outcome. We will determine if those with previously identified detoxification fear show expected difficulty in completing detoxification. We will accomplish this through on site detailed chart reviews and personal interviews with fear subjects from the cohort who remain. We will carefully assess fear subjects to determine if they have not received treatment for their fear and analyze the data separately from those who have. Whether or not investigators' hypotheses are supported, the study will provide scientifically useful methadone maintenance and detoxification outcome data on a large random sample of treated patients from 3 geographically, culturally and racially different subpopulations.